class City {
  public String name;
  public Double latitude;
  public Double longitude;
}

class Person {
  private String name;
  private int age;

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public int getAge() {
    return age;
  }

  public void setAge(int age) {
    this.age = age;
  }
}

public class Main {
  // 给Person类增加getAge/setAge方法：
  private static void demo2() {
    Person ming = new Person();
    ming.setName("小明");
    ming.setAge(12);
    System.out.println(ming.getAge());
  }

  public static void main(String[] args) {
    // 请定义一个City类，该class具有如下字段:
    // name: 名称，String类型
    // latitude: 纬度，double类型
    // longitude: 经度，double类型
    // 实例化几个City并赋值，然后打印。
    City bj = new City();
    bj.name = "Beijing";
    bj.latitude = 39.903;
    bj.longitude = 116.401;
    System.out.println(bj.name);
    System.out.println("location: " + bj.latitude + ", " + bj.longitude);

    
  }
}